ISOLATION OF PAH DEGRADING BACTERIA FROM OIL CONTAMINATED SOIL OF DARKHOVEYN

Background and Aim:Polycyclic aromatic hydrocarbons (PAHs) are the most toxic and carcinogenic pollutants and cause serious damage to humans and the environment. Soils contaminated with petroleum compounds usually have bacteria that degrade these compounds, which grow on PAHs as carbon and energy sources. This study aimed to find such bacteria.Methods:Soil contaminated with oil was collected near one of the wells in Darkhoveyn, 40 km from Abadan, and analyzed by high performance liquid chromatography (HPLC). 0.5 gr of this soil was added to 100 mL of nutrient broth with nystatin and cycloheximide, each at a concentration of 50 mg/L. flasks were incubated in an incubator shaker at 30°C overnight. Then mineral salt medium (MSM) with 0.5%w/v SDS was used to grow bacteria and 10 gr/L of naphthalene, anthracene and phenanthrene were added to the flasks as carbon sources, separately. After two weeks, OD660 was considered as a measure of the bacterial growth.Results:The total amount of soil aromatics was 1855 µg/kg. The various compound concentrations were: Naphthalene 134, Phenanthrene 425, Anthracene 3.8, Fluoranthene 170, Pyrene 263, Benz[a]anthracene 190, Chrysene 508, Dibenz[a,h]anthracene 71 and Benzo[ghi]Perylene 45 µg/kg. The mean absorption at 660nm for naphthalene, anthracene and phenanthrene was respectively 0.4, 0.12 and 0.15 with two replications.Conclusion:According to the findings, these bacteria can use naphthalene, anthracene and phenanthrene as the only carbon source and they are capable bacteria in bioremediation.

Keywords:

Polycyclic aromatic hydrocarbons , Carbon source , Biodegradation